The shortest distance between skew lines

1. Click for point A and B on L1 and L2; 2. Click for the directional vectors v1 and v2 of L1 and L2; 3. Click for vector joining L1 and L2 i.e. vector a = vector AB; 4. Click for vector b the vector product of v1 and v2; 5. Click for shortest distance between the skew lines L1 and L2 this is achieved by calculating the scalar projection of vector a onto vector b; 6. Move the slider to move point B on L2, notice that the projection does not change; 7. Use Rotate 3D Graphics View" to see from different perspectives; 8. For full 3D effect: Right click select Graphics - 3D Graphics - Projection - Glasses. Move the view to the right using your mouse and then put on your red-cyan 3D glasses and enjoy.